Weight reduction is a goal of most manufacturers of automotive vehicles in that reductions in weight increase fuel economy which in turn reduces emissions. Weight reduction in one vehicle model results in fuel economies which are applicable to fleet wide average fuel economy helping manufacturers achieve a better corporate average fuel economy (CAFE).
A particular target for reductions in vehicle weight and fuel economy are reductions for full-size light-duty trucks and full-size light-duty sport utility vehicles. Transmission cross members for such vehicles are currently made of steel which has a relatively large specific gravity of about 7.8. Metals which are of increasing interest with respect to automotive framing components are magnesium, aluminum and titanium. While magnesium has a specific gravity of 1.74 and aluminum has a specific gravity of 2.70, both of these metals are expensive for mass production of vehicles. Moreover, magnesium requires unusual fasteners and must be protected from galvanic corrosion. Titanium has specific gravity of 4.50, however mass production is quite expensive.
In view of these considerations there is a general need for weight reduction of automotive framing members and a specific need for weight reduction of transmission cross members, wherein the weight reduction does not compromise the stiffness of the members and is achieved with reductions in expense.